Section 25 Understanding and Diagnosing Restless Legs Syndrome

Restless legs Syndrome (RLS) (also called Ekbom's syndrome) is a poorly understood disorder affecting up to 5% of the general population. Characteristics of RLS include the following: RLS is sometimes described as a sense of unease and weariness in the lower leg that is relieved by movement. It is often accompanied by an inability to fall asleep. Patients may describe the symptoms as “pulling, searing, drawing, or crawling” beneath the skin, usually in the calf area. Itching and pain may be present. About 80% of patients with RLS also experience periodic limb movement disorder, also called PLMD (formerly known as nocturnal myoclonus). In PLMD, the leg muscles involuntarily and repetitively contract and jerk every 20 to 40 seconds during sleep. The contractions occasionally arouse patients, but often they are unaware of the interruption. (It should be noted that PLMD is a specific disorder and only about 30% of people with it also have RLS.) These sensations may also affect thighs, feet, and even arms. In fact, a small 2000 study suggested that nearly half of patients may experience RLS-type symptoms in the upper part of the body, specifically the arms. At night the unpleasant sensations and the resulting uncontrollable urge to move the legs can often disturb sleep. Throughout the day the patient may feel compelled to move his or her legs in order to relieve the symptoms. Symptoms typically occur at 30 to 60 second intervals when the legs are at rest (ie, sitting or lying). Symptoms of PLMD and RLS usually fall between 10:00 PM and 4:00 AM, being at their worst right after midnight. Symptoms are at their lowest level between 9:00 and 11:00 AM. Such periodic events indicate that these conditions may be influenced by circadian rhythm (the normal cycle of biologic activity over a 24-hour period). Some experts now believe there are two forms of RLS, early and late-onset, and that each has different characteristics: One study reported that people with the onset of RLS in adolescence or earlier tend to have a family history of the disorder and to have RLS without accompanying pain. Those with later onset tend not to have a family history of RLS and may have a higher rate of pain in the lower extremities.

What Causes Restless Legs Syndrome?
The primary cause of restless legs syndrome is not known. Researchers are investigating neurologic problems that may arise either in the spinal cord or the brain. Such problems most likely have a genetic basis in many cases.

Neurologic Abnormalities in the Spine: Some evidence suggests that restless legs syndrome may be due to nerve impairment in the spinal cord. Until recently, this was believed to be located in the lower back. A recent study reporting symptoms in the arms, however, suggests that nerve damage may occur in the upper spine.

Neurologic Abnormalities in the Brain: Other researchers believe that the neurologic abnormalities involved with RLS are more likely to originate in the brain and be due to imbalances in certain neurotransmitters (chemical messengers in the brain). A variety of studies support the hypothesis that an imbalance in the neurotransmitters dopamine and serotonin may play a part in RLS. Dopamine and serotonin unleash an array of nerve impulses that affect muscle movement. Genetic factors may be a factor in dopamine imbalance. A similar effect is seen in Parkinson's disease, and indeed, drugs that increase dopamine are used for both disorders [see Medications for Restless Legs Syndrome below].

Iron Insufficiency: Iron deficiency has been linked to RLS in some people and may affect dopamine receptors in the brain. In one 2001 study of 10 people, for example, magnetic resonance imaging (MRI) scans found iron insufficiency in parts of the brains of RLS patients. Other studies have also found an association and some suggest that RLS may occur in between 25% and 30% of people with iron deficiencies.

How Is Restless Legs Syndrome Diagnosed? Taking a Sleep History: A diagnosis of restless legs syndrome or nocturnal leg cramps often relies solely on the patient's description of symptoms. In general, the recommended approach is first to take a sleep and personal history. The physician may begin an interview that may include the following questions:How would the sleep problem be described? How long has the sleep problem been experienced? How long does it take to fall asleep? How many times a week does it occur? How restful is sleep? What are the leg problems like (cramps, twitching, crawling feelings)? What is the sleep environment like? Noisy? Not dark enough? What medications are being taken (including the use of self-medications for insomnia, such as herbs, alcohol, and over-the-counter or prescription drugs)? Is the patient taking or withdrawing from stimulants, such as coffee or tobacco? How much alcohol is consumed per day? What stresses or emotional factors may be present? Has the patient experienced any significant life changes? Does the patient snore or gasp during sleep (an indication of sleep apnea)? If there is a bed partner, is his or her behavior distressing or disturbing? Is the patient a shift worker?

Sleep Diary. If the patient cannot answer these questions, keeping a sleep diary is a helpful diagnostic tool. Every day for two weeks, the patient should record all sleep-related information, including responses to questions listed above described on a daily basis. A bed partner can help by adding his or her observations of the patient's sleep behavior.

Sleep Disorders Centers: A physician can recommend a sleep specialist or a sleep disorders center for patients with severe restless legs syndrome. Centers are accredited by the American Academy of Sleep Medicine. Patients should investigate centers carefully, being sure that they offer full sleep studies. Among the signs that may indicate a need for a sleep disorders center are the following: Insomnia due to psychologic disorders. Sleeping problems due to substance abuse. Snoring and sudden awakening with gasping for breath (possible sleep apnea). Severe restless legs syndrome. Persistent daytime sleepiness. Sudden episodes of falling asleep during the day (possible narcolepsy). At most, sleep disorders centers patients undergo an in-depth analysis, usually supervised by a multidisciplinary team of consultants who can provide both physical and psychiatric evaluations.
- Leg Disorders (Restless Legs Syndrome and Nocturnal Leg Cramps). Leg Disorders Annual Report (Restless Legs Syndrome, Intermittent Claudication, & Nocturnal Leg Cramps), 2002, p1, 11p

Personal
Reflection Exercise #11The preceding section contained information
about understanding and diagnosing Restless Legs Syndrome. Write
three case study examples regarding how you might use the content of this section
in your practice.

QUESTION 25 What are the primary symptoms of Restless Legs Syndrome? Record the letter of the correct answer
the Answer
Booklet.